The GU-47A tetrode is used as a power amplifier at frequencies up to 70 MHz

GENERAL
Cathode: directly heated, carbonized thoriated tungsten
Envelope: glass-to-metal with ring leads of cathode and grids
Cooling: forced (water for anode, air for stem).
Height: at most 260 mm.
Diameter: at most 91 mm.
Mass: at most 2 kg